Volkswagen is presenting one of its most fuel-efficient vehicles at the Detroit auto show, the 2013 Jetta hybrid. VW says the car gets 45 mpg combined and will be able to hit speeds of 44 mph on electric power alone.

The Jetta hybrid will be motivated by a 1.4-liter turbocharged engine developing 150 hp, while the electric motor adds 27 hp. The unit puts out 184 lb-ft of twist and weighs in at just 216 pounds. On hard acceleration, both engine and battery combine to make 170 hp. Power is transferred through VW's seven-speed dual-clutch transmission, which was downsized for this application to 163 pounds.

A 220-volt, 1.1-kilowatt-hour, lithium-ion battery behind the rear seat supplies energy to the motor. It consists of 60 individual cells with a combined energy capacity of five amp hours. A fan is mounted to the battery for cooling. It also has its own management system that performs safety, diagnostic and monitoring functions and temperature management.

Regenerative braking is part of the efficiency package. It feeds kinetic energy back to the battery when the brakes are applied. It works even more efficiently with the dual-clutch because the transmission is decoupled immediately after the gas pedal is released. Instead of the car using the engine, transmission and brakes to slow, all of the work is put on the regenerative system.

Not only is the transmission decoupled, but at a stoplight or even when cruising, the motor can shut off completely. Accessories stay on using battery power even when the engine goes into stop mode. When the brake is released or the gas pedal is depressed, the engine kicks back on.

All of the relevant hybrid information is displayed on the instrument cluster, including an energy-flow diagram, battery-charge state and ePower meter. The ePower is active only in electric driving and boost mode. The ePower meter replaces the tach on the left side of the instrument cluster and informs the driver of the operating state of the Jetta. The states are Ready, a general readiness to drive; Charge, battery regeneration; Eco, eco-conscious driving mode; Boost, boosting; or Off, when driving with the internal-combustion engine alone.

To add more mpgs, the Jetta hybrid gets a new front airdam, a rear diffuser and an integrated rear spoiler. As a result, the hybrid's coefficient of drag is 10 percent lower than that of a stock Jetta. Low-rolling-resistance tires are wrapped around 15-inch alloy wheels.

There's also a different radiator grille with a VW logo, integrated on a blue background for the first time. Hybrid signatures will adorn the grille, front fenders and rear deck.

The 2013 Jetta hybrid will launch in North America at the end of 2012. Pricing information isn't available but expect it to come in at about the same price of the small hybrid sedans.